1. Field of the Invention
The present invention generally relates to method, system and software product used in finite element analysis, more particularly to numerically simulating of the structural behaviors of a guided cable contact.
2. Description of the Related Art
Finite element analysis (FEA) is a computerized method widely used in industry to model and solve engineering problems relating to complex systems. FEA derives its name from the manner in which the geometry of the object under consideration is specified. With the advent of the modern digital computer, FEA has been implemented as FEA software. Basically, the FEA software is provided with a model of the geometric description and the associated material properties at each point within the model. In this model, the geometry of the system under analysis is represented by solids, shells and beams of various sizes, which are called elements. The vertices of the elements are referred to as nodes. The model is comprised of a finite number of elements, which are assigned a material name to associate with material properties. The model thus represents the physical space occupied by the object under analysis along with its immediate surroundings. The FEA software then refers to a table in which the properties (e.g., stress-strain constitutive equation, Young's modulus, Poisson's ratio, thermo-conductivity) of each material type are tabulated. Additionally, the conditions at the boundary of the object (i.e., loadings, physical constraints, etc.) are specified. In this fashion a model of the object and its environment is created.
FEA is becoming increasingly popular with automobile manufacturers for optimizing both the aerodynamic performance and structural integrity of vehicles. Similarly, aircraft manufacturers rely upon FEA to predict airplane performance long before the first prototype is built. Rational design of semiconductor electronic devices is possible with Finite Element Analysis of the electrodynamics, diffusion, and thermodynamics involved in this situation. FEA is utilized to characterize ocean currents and distribution of contaminants. FEA is being applied increasingly to analysis of the production and performance of such consumer goods as ovens, blenders, lighting facilities and many plastic products. In fact, FEA has been employed in as many diverse fields as can be brought to mind, including plastics mold design, modeling of nuclear reactors, analysis of the spot welding process, microwave antenna design, simulating of car crash and biomedical applications such as the design of prosthetic limbs. In short, FEA is utilized to expedite design, maximize productivity and efficiency, and optimize product performance in virtually every stratum of light and heavy industry. This often occurs long before the first prototype is ever developed.
Generally, FEA begins by generating a finite element model of a system. In this model, a subject structure is reduced into a number of node points which are connected together to form finite elements. Governing equations of motion are written in a discrete form, where the motions of each node point are the unknown part of the solution. A simulated load or other influence is applied to the system and the resulting effect is analyzed using well known mathematical methods.
FEA software can be classified into two general types, implicit FEA software and explicit FEA software. Implicit FEA software uses an implicit equation solver to solve a system of coupled linear equations. Such software is generally used to simulate static or quasi-static problems. Explicit FEA software does not solve coupled equations but explicitly solves for each unknown assuming them uncoupled. Explicit FEA software usually uses central difference time integration which requires very small solution cycles or time steps for the method to be stable and accurate. Explicit FEA software is generally used to simulate short duration events where dynamics are important such as impact type events.
One of the most challenging FEA tasks is to simulate an impact event such as car crash. With the advance of the computer technologies and with the advantage of parallel processing, the FEA model for the car crash simulation has become very sophisticated. The number of elements to model a car has increased from several thousands a decade ago to more than one million today. Instead of using a few rigid links to model the dummy driver, a very complicated bio-mechanical human model is used in today's model. In order to model the bio-mechanical model adequately, the spinal column must be included. This leads to a new challenge to numerically simulate the behaviors of the spinal column. It is therefore desirable to have a new method to numerically simulate a human model in a car crash analysis more efficiently and effectively.